What are GICs?
Geomagnetic Induced Currents, GICs, are the product of large variations in the magnetic inducing electric fields in the earth, which are caused by geomagnetic storms.
GICs flow in metallic pipelines, underground cables, communication systems, railways, and transmission lines and stations in the power system.
When flowing through the various elements in a power grid, GICs produce undesirable quasi direct currents, which can be superimposed on alternating currents within the grid. GICs may result in unbalanced conditions, resulting in damage to critical transformers.
Introduction of GICs into the power system poses two major risks, namely:
- Damage to bulk power assets, typically associated with power transformers.
- Loss of reactive power support, which could lead to voltage instability and power system collapse.
Potential Effects of GICs
A major geomagnetic disturbance, GMD, occurred in 1989, which led to the collapse of the Hydro Québec system. This event left six million people without service for nine hours or longer.
Solar activity follows an 11 year cycle, with the most intense events occurring near the cycle peak. The risk of intense geomagnetic storms is elevated as the peak of a current solar cycle is approached. For the current cycle, the Space Weather Prediction Center projects the geomagnetic storm risk to peak between 2013 and 2015.
In January 2014, FERC proposed to adopt a new reliability standard intended to mitigate effects of GMDs, as they pose potentially severe, widespread effects on the reliable operation of the bulk-power transmission system. NERC is required to file the second stage reliability standards in January 2015.
How Teshmont Can Help
Teshmont’s experienced team can perform studies to calculate GIC flow and reactive power losses of a power system. Various geoelectric field scenarios can be explored by taking into account the key geophysical factors associated with the geomagnetic induction process. Geoelectric field scenarios can be mapped into the system using the temporal profile and maximum GIC flow in the major power transformers and transmission lines, which provide a profile of maximum reactive power losses.
Once reactive power losses are identified, various mitigation approaches can be applied to address vulnerable and critical power transformers.